both/and

Much of Proverbs consists of statements in parallel form, with the second line either contrasting with or building on the first line -- a distinguishing characteristic of Hebrew poetry called parallelism.

The plans of the heart belong to man,
but the answer of the tongue is from the LORD.
- Proverbs 16:1


The heart of man plans his way,
but the LORD establishes his steps.
- Proverbs 16:9

The Reformation Study Bible comments on these two proverbs.

The sages occasionally remind us that human responsibility to reason and act does not contradict God's sovereignty.

Paul states the same principal using a similar parallel form.

Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, for it is God who works in you, both to will and to work for his good pleasure.
- Philippians 2:12-13 (ESV)